Self-contained fuel cell and cartridge therefor

ABSTRACT

Fuel cell including a casing, a cathode having a first surface and a second surface, at least part of the second surface being exposed to the atmosphere, an anode having a first surface and a second surface, a first chamber configured to retain liquid fuel, wherein the first chamber is defined at least partially by the first surface of the anode, and a second chamber configured to retain liquid electrolyte, wherein the second chamber is defined at least partially by the second surface of the anode and the first surface of the cathode, wherein the fuel cell is configured to be sealed in a substantially liquid-tight manner during at least a portion of its service life. A cartridge can be connected to the fuel cell. This Abstract is not intended to define the invention disclosed in the specification, nor intended to limit the scope of the invention in any way.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims the benefit of U.S. ProvisionalPatent Application No. 60/453,218, filed on Mar. 11, 2003 under 35U.S.C. §119(e), the disclosure of which is expressly incorporated byreference herein in its entirety.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a self-contained fuel cell and acartridge therefor. The invention also relates to a refillable fuel celland a refilling device.

[0004] 2. Discussion of Background Information

[0005] An electrochemical fuel cell is a device that converts the energyof a chemical reaction into electricity. Among the advantages that fuelcells have over other sources of electrical energy are a high efficiencyand environmental friendliness. Although fuel cells are increasinglygaining acceptance as electrical power sources, there are technicaldifficulties that prevent the widespread use of fuel cells in manyapplications, especially mobile and portable applications. A fuel cellproduces electricity by bringing a fuel into contact with a catalyticanode while bringing an oxidant into contact with a catalytic cathode.When in contact with the anode, the fuel is oxidized at catalyticcenters to produce electrons. The electrons travel from the anode to thecathode through an electrical circuit connecting the electrodes.Simultaneously, the oxidant is catalytically reduced at the cathode,consuming the electrons generated at the anode. Mass balance and chargebalance are preserved by the corresponding production of ions at eitherthe cathode or the anode and the diffusion of these ions to the otherelectrode through an electrolyte with which the electrodes are incontact. As the fuel cell produces electricity, the liquid fuel and theelectrolyte are gradually exhausted of their useful components.Consequently, fresh liquid fuel must continuously be supplied to knownfuel cells. In other words, at least during operation, liquid (andother) fuel cells are open systems, because they depend on the constantsupply of fresh fuel (and fresh electrolyte) from the exterior. It wouldbe very desirable to have available a fuel cell that is capable of beingoperated in a substantially sealed state, similar to a battery. It wouldalso be desirable to be able to reuse this sealed fuel cell after theliquid fuel and/or the liquid electrolyte are exhausted.

SUMMARY OF THE INVENTION

[0006] The present invention provides a fuel cell comprising a casingand, within the casing (i.e., partially or completely within thecasing), a cathode having a first surface and a second surface, at leastpart of the second surface being exposed to the atmosphere, and an anodehaving a first surface and a second surface. The fuel cell furthercomprises at least one first chamber for holding fuel and at least onesecond chamber for holding electrolyte. The first chamber is defined atleast partially by the first surface of the anode and the second chamberis defined at least partially by the second surface of the anode and thefirst surface of the cathode. This fuel cell is configured to be sealedin a substantially liquid-tight manner during at least a portion of thetime that it is in service.

[0007] In one aspect, the fuel cell is configured to not be connected toa fuel delivery system during at least a portion of the time that it isin service.

[0008] In another aspect, the first chamber is filled at least partially(e.g., completely) with a liquid (or at least fluid) fuel and the secondchamber is filled at least partially (e.g., completely) with a liquid(or at least fluid) electrolyte.

[0009] In yet another aspect, the casing is configured to be capable ofbeing substantially liquid-tight regardless of orientation (preferably,however, the casing is not gas-tight).

[0010] In a further aspect, the liquid fuel comprises a (monohydric orpolyhydric) lower alcohol and/or LiAlH₄, KBH₄, NaBH₄, LiBH₄,(CH₃)₃NHBH₃, NaAlH₄, NaCNBH₃, CaH₂, LiH, NaH, KH, Na₂S₂O₃, Na₂HPO₃,Na₂HPO₂, K₂S₂O₃, K₂HPO₃, K₂HPO₂, NaCOOH, KCOOH or any combination of twoor more thereof.

[0011] In another aspect, the liquid electrolyte comprises an aqueousinorganic hydroxide, for example, an alkali metal hydroxide such as,e.g. potassium hydroxide.

[0012] In still other aspects, the cathode comprises an air-breathingcathode and/or the anode comprises a metal that is capable of catalyzingthe electrochemical oxidation of the liquid fuel.

[0013] In a further aspect, the fuel cell does not comprise a membrane.

[0014] In yet another aspect, the first chamber is capable of holding upto about 2000 ml of liquid (fluid) fuel, e.g., from about 1 to about1000 ml of liquid fuel and/or the second chamber is capable of holdingup to about 1000 ml of liquid fuel, e.g., from about 0.5 to about 500 mlof liquid fuel.

[0015] According to another aspect, the free inner volume of the fuelcell is up to about 4000 ml, e.g., from about 1.5 to about 3000 ml.

[0016] In another aspect, the casing has outer surfaces that are of agenerally rectangular shape and/or the largest outer dimension of thecasing is not larger than about 50 cm.

[0017] In still another aspect, the useful surface area of the cathodeand/or the anode is from about 0.5 to about 500 cm².

[0018] According to yet another aspect, at least some parts of thecasing are made of a plastic material. Non-limiting examples thereof area polyolefin (e.g., polyethylene, polypropylene) polycarbonate,polyvinylchloride, acrylonitrile-butadiene-styrene (ABS) terpolymer,polyurethane, polytetrafluoroethylene, silicone rubber and anycombination of two or more thereof, provided, of course, these materialscan withstand the chemical attack by the liquids they may come intocontact with.

[0019] In another aspect, at least some parts of the casing are made ofa metal and/or a metal alloy. Non-limiting examples thereof arestainless steel, nickel, chromium, titanium and any combination of twoor more thereof.

[0020] In a still another aspect, the casing comprises at least onesealable opening for each of the first and second chambers, e.g., twosealable openings for each of the first and second chambers. These twosealable openings for each chamber may, for example, be disposed at orclose to opposite ends of the respective chamber.

[0021] In another aspect, the casing is capable of being subjected tomultiple opening and resealing operations. For example, the sealableopenings may comprise valves.

[0022] In still another aspect, the second surface of the anode and thefirst surface of the cathode are substantially parallel to each other.

[0023] In a further aspect, the fuel cell comprises one first chamberand one second chamber; or one first chamber and two second chambers; ortwo first chambers and two second chambers.

[0024] In another aspect, the fuel cell comprises more than one cathode,more than one anode and more than one second chamber for holding liquidelectrolyte. For example, the fuel cell may comprise first and secondanodes, first and second cathodes, a single chamber for holding liquidfuel and first and second chambers for holding liquid electrolyte. Byway of non-limiting example, in this embodiment the first chamber forholding liquid electrolyte may be defined at least partially by thefirst cathode and the first anode, the second chamber for holding liquidelectrolyte may be defined at least partially by the second cathode andthe second anode, and the fuel chamber may be defined at least partiallyby the first and second anodes.

[0025] In another aspect, the casing comprises at least one sealableopening for allowing gas generated during the operation of the fuel cellto escape to the surrounding atmosphere.

[0026] In yet another aspect, the fuel cell further comprises anancillary power supply device for peak power requirements, for example,a supercapacitor.

[0027] The present invention also provides a self-contained, refreshablefuel cell comprising at least one cathode, at least one anode and atleast one first and second chamber as set forth above. The first andsecond chambers each have at least one sealable opening for replacingspent liquid by fresh liquid, for example, two sealable openings, oneopening for discharging spent liquid and another opening for filling thefirst (second) chamber with fresh liquid.

[0028] The present invention further provides a cartridge for refreshingthe fuel cell set forth above. The cartridge comprises at least one fuelchamber that is filled at least partially (e.g., substantiallycompletely) with the liquid (fluid) fuel and/or at least one electrolytechamber that is filled at least partially (e.g., substantiallycompletely) with the liquid (fluid) electrolyte.

[0029] In one aspect, the fuel and electrolyte chambers each have atleast one sealable opening, for example, two sealable openings (e.g., ator close to opposite ends of the chambers). These sealable openings maycomprise, e.g., valves.

[0030] In another aspect of the cartridge, the liquid fuel and/or theliquid electrolyte contained therein is the same or similar to theliquid fuel/liquid electrolyte used for the fuel cell set forth above.

[0031] In still another aspect of the cartridge, a fuel chamber thereofis capable of holding up to about 2500 ml of liquid fuel, e.g., fromabout 1.5 to about 1250 ml of liquid fuel, and/or an electrolyte chamberthereof is capable of holding up to about 1500 ml of liquid electrolyte,e.g., from about 1 to about 750 ml of liquid electrolyte.

[0032] In a further aspect, the free inner volume of the cartridge is upto about 5000 ml, e.g., from about 2 to about 4000 ml.

[0033] In yet another aspect, the outer surfaces of the cartridge are ofa generally rectangular shape and/or the largest outer dimension of thecartridge is not larger than about 50 cm.

[0034] In another aspect, at least some parts of the cartridge are madeof a plastic material. Non-limiting examples thereof are a polyolefin(e.g., polyethylene, polypropylene), polycarbonate, polyvinylchloride,acrylonitrile-butadiene-styrene (ABS) terpolymer, polyurethane,polytetrafluoroethylene, silicone rubber and any combination of two ormore thereof, provided, of course, these materials can withstand thechemical attack by the liquids they may come into contact with.

[0035] In still another aspect, the cartridge comprises one fuel chamberand one electrolyte chamber; or one fuel chamber and two electrolytechambers; or two fuel chambers and two electrolyte chambers.

[0036] The present invention furthermore provides a packaged combinationof a plurality of cartridges as set forth above, wherein the combinationcomprises at least one first cartridge filled at least partially (e.g.,substantially completely) with the liquid (fluid) fuel and at least onesecond cartridge filled at least partially (e.g., substantiallycompletely) with the liquid (fluid) electrolyte. For example, thecombination may comprise 1 to about 20 first cartridges and one secondcartridge.

[0037] The present invention furthermore provides a fuel cellcombination comprising the fuel cell as set forth above (including thevarious aspects thereof) and a cartridge for refreshing at least one ofthe liquid fuel and the liquid electrolyte contained in the fuel cell.The cartridge may be a cartridge as set forth above (including thevarious aspects thereof).

[0038] In one aspect, the chambers of the fuel cell and the chamber(s)of the cartridge each have at least one sealable opening. The sealableopenings of the chambers of the fuel cell and the sealable opening(s) ofthe chamber(s) of the cartridge may be configured to be capable offorming a liquid-tight passageway for liquid flowing between a chamberof the fuel cell and the corresponding chamber of the cartridge.

[0039] In another aspect, each chamber of the fuel cell and each chamberof the cartridge has two sealable openings which are disposed at orclose to opposite ends of the respective chamber.

[0040] In yet another aspect, the sealable openings of each chamber ofthe fuel cell and the sealable openings of each chamber of the cartridgeare disposed with respect to each other to allow a substantiallysimultaneous flow of spent and refreshening liquids into and out of eachchamber.

[0041] In a still further aspect, the volume ratio of a chamber of thefuel cell and a chamber of the cartridge corresponding thereto (and/orthe volume ratio of the liquid contained in a chamber of the fuel celland the liquid contained in a chamber of the cartridge correspondingthereto) is from about 1:1 to about 1:1.4.

[0042] In yet another aspect of the combination, the cartridge comprisesa pumping mechanism for pushing the liquid in a chamber thereof into acorresponding chamber of the fuel cell.

[0043] The present invention further provides a method of supplyingelectrical energy to a device. The method comprises providing a fuelcell as set forth above (including the various aspects thereof) andestablishing electrical contact between the device and the fuel cell,the fuel cell being sealed in a substantially liquid-tight manner andnot connected to an external fuel delivery system while the fuel cellsupplies electrical energy to the device.

[0044] The present invention also provides a device connected to thefuel cell as set forth above. The fuel cell is sealed in a substantiallyliquid-tight manner and not connected to an external fuel deliverysystem. The device may be a portable device and/or an electronic device,e.g., a telecommunications device.

[0045] In one aspect, the device is a cellular phone, portable computer,PDA, audio device, video device, medical device or a component thereof.For example, the device may have a power capacity of up to about 150 W.

[0046] The present invention furthermore provides a method of refreshinga self-contained fuel cell as set forth above. The method comprisesproviding a cartridge as set forth above wherein each of the fuel andelectrolyte chambers has at least one sealable opening that isconfigured to be capable of establishing a liquid-tight passageway whencontacted with a sealable opening of the corresponding chamber of thefuel cell; contacting the sealable openings of a chamber of the fuelcell and a corresponding chamber of the cartridge to establish asubstantially liquid-tight passageway between the chambers; and allowingand/or causing the liquid contained in a chamber of the cartridge toflow into a corresponding chamber of the fuel cell and vice versa.

[0047] As set forth above, the fuel cell of the present invention isconfigured to be sealed in a substantially liquid-tight manner during atleast a portion of the time that it is in service (e.g., during theentire time it is in use). In other words, the fuel cell is notdependent on an external supply of fuel/electrolyte, but isself-contained, i.e., is comparable to a conventional battery in thisregard. A conventional battery includes a metal as an integral source ofenergy. The fuel cell of the present invention, on the other hand, isconfigured to contain a liquid (fluid) fuel as an integral source ofenergy, wherefore it does not have to be connected to a fuel deliverysystem when it is in service. Whereas a conventional battery needs to bereplaced once it is exhausted (the metal is used up), with the fuel cellof the present invention only the energy source needs to be replaced,i.e., the fuel cell may be reused after the spent fuel/electrolyte hasbeen replaced by fresh fuel/electrolyte.

[0048] The fuel for the fuel cell of the present invention may be anyknown liquid (fluid) fuel for fuel cells. By way of non-limitingexample, the fuel may comprise a (monohydric or polyhydric) loweralcohol, optionally in combination with a solid fuel such as, e.g.,LiAlH₄, KBH₄, NaBH₄, LiBH₄, (CH₃)₃NHBH₃, NaAlH₄, NaCNBH₃, CaH₂, LiH,NaH, KH, Na₂S₂O₃, Na₂HPO₃, Na₂HPO₂, K₂S₂O₃, K₂HPO₃, K₂HPO₂, NaCOOH,KCOOH or any combination of two or more thereof. The lower alcohol may,for example, be an alcohol having 1 to 6, e.g., 1 to 4 carbon atoms,and, e.g., 1 to 4 OH groups. Non-limiting examples thereof are methanol,ethanol, n-propanol, isopropanol, n-butanol, isobutanol, pentanol,hexanol, ethylene glycol, propylene glycol, glycerol, pentaerythritoland any combination of two or more thereof. The fuel may also comprise abasic compound, e.g., for the purpose of stabilizing the solid fuel. Thebasic compound may, for example, be an inorganic hydroxide, non-limitingexamples whereof are ammonium and (alkali and alkaline earth) metalhydroxides, such as, e.g., NaOH, KOH, LiOH, NH₄OH, Ca(OH)₂ and Mg(OH)₂.

[0049] The liquid (fluid) electrolyte for use in the present fuel cellmay comprises a base, for example an aqueous inorganic hydroxide.Non-limiting examples of the inorganic hydroxide are ammonium and(alkali and alkaline earth) metal hydroxides, such as, e.g., NaOH, KOH,LiOH, NH₄OH, Ca(OH)₂ and Mg(OH)₂.

[0050] Non-limiting examples of fuels and electrolytes suitable for usein the fuel cell of the present invention are disclosed in U.S. PatentApplication Publication Nos. 2002/0083640, 2002/0094459, 2002/0142196,in co-pending U.S. patent application Ser. No. 10/230,204, and U.S. Pat.Nos. 5,599,640 and 5,804,329, the entire disclosures whereof are herebyincorporated herein by reference.

[0051] The capacity of the at least one first chamber of the fuel cellof the present invention is not particularly limited. Usually, however,the first chamber will be capable of holding up to about 2000 ml offuel, e.g., up to about 1500 ml, up to about 1000 ml, up to about 500ml, up to about 250 ml, up to about 100 ml, up to about 50 ml, or up toabout 25 ml of fuel. On the other hand, the first chamber usually willbe capable of holding at least about 1 ml of fuel, e.g., at least about2 ml, at least about 5 ml, at least about 10 ml, at least about 15 ml,or at least about 20 ml of fuel.

[0052] The capacity of the at least one second chamber of the fuel cellof the present invention is not particularly limited, either. Usually,however, the second chamber will be capable of holding up to about 1000ml of electrolyte, e.g., up to about 750 ml, up to about 500 ml, up toabout 250 ml, up to about 100 ml, up to about 50 ml, or up to about 25ml of electrolyte. On the other hand, the second chamber usually will becapable of holding at least about 0.5 ml of electrolyte, e.g., at leastabout 1 ml, at least about 2 ml, at least about 5 ml, at least about 10ml, at least about 15 ml, or at least about 20 ml of electrolyte.

[0053] The free inner volume of the fuel cell of the present invention(i.e., the inner volume of the fuel cell that is capable of beingoccupied by gas and/or liquid) is not particularly limited, but usuallywill be up to about 4000 ml, e.g., up to about 3000 ml, up to about 2000ml, up to about 1000 ml, up to about 500 ml, up to about 250 ml, up toabout 100 ml, or up to about 50 ml. Usually, the free inner volume willnot be smaller than about 1.5 ml, e.g., not smaller than about 3 ml, notsmaller than about 5 ml, not smaller than about 10 ml, not smaller thanabout 15 ml, not smaller than about 20 ml, or not smaller than about 25ml.

[0054] The useful surface areas of the cathode(s) and the anode(s) ofthe fuel cell of the present invention are not particularly limited.Usually, however, in the case of both an anode and a cathode theseuseful surface areas (i.e., the surface areas that are capable of cominginto direct contact with the fuel/electrolyte) are at least about 0.5cm², e.g., at least about 2 cm², at least about 5 cm², at least about 10cm², at least about 20 cm², or at least about 30 cm². On the other hand,the useful surface areas usually are not larger than about 500 cm²,e.g., not larger than about 300 cm², not larger than about 200 cm², notlarger than about 100 cm², not larger than about 75 cm², or not largerthan about 50 cm².

[0055] The casing of the fuel cell of the present invention may haveouter surfaces that are of a generally rectangular shape and the largestouter dimension of the casing may not be larger than about 50 cm. Theterm “generally rectangular shape” includes shapes which are notperfectly rectangular, e.g., wherein one or more of the angles of the“rectangles” are slightly different from 90° (e.g., between about 80°and about 100°) and/or rectangular shapes having rounded comers and/oredges. Of course, the fuel cell of the present invention may take anynon-rectangular shape as well, e.g., a cylindrical shape (e.g., similarto conventional batteries). The “largest outer dimension” of the fuelcell may, for example be any one of, e.g., the height, width, depth anddiameter of the fuel cell. This largest outer dimension may, forexample, not be larger than about 40 cm, e.g., not larger than about 30cm, not larger than about 20 cm, not larger than about 15 cm or notlarger than about 10 cm. On the other hand, the largest outer dimensionusually will not be smaller than about 1 cm, e.g., not smaller thanabout 2 cm, or not smaller than about 5 cm.

[0056] In a preferred embodiment, the casing of the fuel cell of thepresent invention comprises at least one (substantially) sealableopening for each of its chambers (the term “sealable opening” as usedherein includes, and preferably relates to, resealable openings, i.e.,the casing is capable of being subjected to multiple opening andresealing operations.). By way of non-limiting example, two sealableopenings for each chamber may be disposed, e.g., at or close to twoopposite ends of each chamber. The term “close to” is meant to indicatethat an opening is spaced apart from one end by not more than about 10%of the entire distance between the opposite ends. A non-limiting exampleof such a sealable opening is described below in the section “DETAILEDDESCRIPTION OF THE PRESENT INVENTION”.

[0057] In another preferred embodiment of the fuel cell of the presentinvention, the casing thereof comprises at least one sealable openingfor allowing gas generated during the operation of the fuel cell toescape to the surrounding atmosphere. Of course, this sealable openingmust be capable of preventing liquid present inside the fuel cell fromleaking. A non-limiting example of such a sealable opening is describedbelow in the section “DETAILED DESCRIPTION OF THE PRESENT INVENTION”. Itis even more preferred for the casing to have two or more such sealableopenings so as to facilitate the escape of gas independent of theorientation of the fuel cell.

[0058] Moreover, the fuel chamber (and also the electrolyte chamber) ofthe fuel cell of the present invention may contain a turbulence reducingarrangement for enhancing the laminar flow inside the chamber during arefilling operation. A non-limiting example of such a turbulencereducing arrangement and an explanation of the operation thereof areprovided below in the section “DETAILED DESCRIPTION OF THE PRESENTINVENTION”.

[0059] The fuel cell of the present invention may further comprise,e.g., an ancillary power supply device for peak power requirements,e.g., a supercapacitor. In particular, certain electric and electronicdevices require very little electric energy during most of the time theyare in operation, but require a substantial amount of energy for shortperiods of time. While the fuel cell may be capable of satisfying theregular energy demand of the device, its capacity may not be enough forthe peak times. The ancillary power supply device (which preferably ischarged by the fuel cell itself) can be used to help satisfy thisincreased, short-term, energy demand.

[0060] The cartridge of the present invention comprises at least onefuel chamber that is filled at least partially (e.g., substantiallycompletely) with the liquid (fluid) fuel, at least one electrolytechamber that is filled at least partially (e.g., substantiallycompletely) with the liquid (fluid) electrolyte, or a combination of oneor more fuel chambers and one or more electrolyte chambers.

[0061] The fuel and electrolyte chambers each have at least onesubstantially sealable opening, e.g., two sealable openings, at or closeto opposite ends of the chambers. A non-limiting example of such asealable opening is described below in the section “DETAILED DESCRIPTIONOF THE PRESENT INVENTION”.

[0062] The fuel and/or the electrolyte contained in the cartridgepreferably is substantially the same as the fuel/electrolyte originallypresent in the fuel cell set forth above. It is noted, however, that thecomposition of the fuel/electrolyte contained in the cartridge does nothave to be the same as the composition of the fresh fuel/electrolyteoriginally present in the fuel cell. The only requirement is that thecartridge fuel/electrolyte for refreshing the fuel cell is capable ofkeeping the fuel cell operative.

[0063] The capacity of a fuel chamber of the cartridge of the presentinvention is not particularly limited. Usually, however, the fuelchamber will be capable of holding up to about 2500 ml of fuel, e.g., upto about 2000 ml, up to about 1500 ml, up to about 1250 ml, up to about1000 ml, up to about 750 ml, up to about 500 ml, up to about 250 ml, upto about 100 ml, up to about 50 ml, or up to about 25 ml of fuel. On theother hand, the fuel chamber will usually be capable of holding at leastabout 1.5 ml of fuel, e.g., at least about 5 ml, at least about 7.5 ml,at least about 10 ml, at least about 15 ml, or at least about 20 ml offuel.

[0064] The capacity of an electrolyte chamber of the cartridge of thepresent invention is not particularly limited, either. Usually, however,the electrolyte chamber will be capable of holding up to about 1500 mlof electrolyte, e.g., up to about 1250 ml, up to about 1000 ml, up toabout 750 ml, up to about 500 ml, up to about 250 ml, up to about 100ml, up to about 75 ml, up to about 50 ml, or up to about 25 ml ofelectrolyte. Also, it will usually be capable of holding at least about1 ml of electrolyte, e.g., at least about 2.5 ml, at least about 5 ml,at least about 7.5 ml, at least about 10 ml, at least about 15 ml, or atleast about 20 ml of electrolyte. As a general rule, for refreshing thefuel cell it is preferable to use a slightly higher volume offuel/electrolyte than the volume of the fuel/electrolyte of the fuelcell that is to be replaced. The excess volume may be used to rinse thefuel chamber/electrolyte chamber, for example to remove any soliddeposits which may have formed in the chamber during the operation ofthe fuel cell. Accordingly, assuming substantially completely filledchambers, a refreshing cartridge for a given fuel cell preferably willcomprise a chamber having a volume that is not less than 110%, e.g., notless than 120%, not less than 130%, or even not less than 140% of thevolume of the corresponding chamber of the fuel cell.

[0065] The (combined) free inner volume of the chamber(s) of thecartridge of the present invention (i.e., the inner volume thereof thatis capable of being occupied by gas and/or liquid) is not particularlylimited. Usually, however, it will be up to about 5000 ml, e.g., up toabout 4000 ml, up to about 3000 ml, up to about 2000 ml, up to about1000 ml, up to about 500 ml, up to about 250 ml, up to about 100 ml, orup to about 50 ml, and it will usually not be smaller than about 2 ml,e.g., not smaller than about 5 ml, not smaller than about 10 ml, notsmaller than about 20 ml, or not smaller than about 30 ml.

[0066] The cartridge of the present invention may have outer surfacesthat are of a generally rectangular shape and the largest outerdimension of the cartridge may not be larger than about 50 cm. The term“generally rectangular shape” includes shapes which are not perfectlyrectangular, e.g., wherein one or more of the angles of the “rectangles”are slightly different from 90° (e.g., between about 80° and about 100°)and/or rectangular shapes having rounded corners and/or edges. Ofcourse, the cartridge of the present invention may take anynon-rectangular shape as well, e.g., a cylindrical shape. The “largestouter dimension”of the cartridge may, for example, be any one of, e.g.,the height, width, depth and diameter of the cartridge. This largestouter dimension may, for example, not be larger than about 40 cm, e.g.,not larger than about 30 cm, not larger than about 20 cm, not largerthan about 15 cm or not larger than about 10 cm. On the other hand, thelargest outer dimension usually will not be smaller than about 1 cm,e.g., not smaller than about 2 cm, or not smaller than about 5 cm.

[0067] The cartridge of the present invention may comprise a singlechamber, i.e., a single fuel chamber or a single electrolyte chamber. Itmay also comprise any combinations thereof, e.g., one fuel chamber andone electrolyte chamber, one fuel chamber and two electrolyte chambers,or two fuel chambers and two electrolyte chambers. Apparently, theconfiguration and the type/number of individual chambers of the fuelcell that the cartridge is intended for will often determine theconfiguration and the type/number of individual chambers of thecartridge.

[0068] The packaged combination of a plurality of cartridges provided bythe present invention comprises at least one first cartridge filled atleast partially (e.g., substantially completely) with a liquid fuel andat least one second cartridge filled at least partially (e.g.,substantially completely) with a liquid electrolyte. Since in many casesthe fuel of a fuel cell will have to be replaced more often than theliquid electrolyte thereof, the combination may comprise 1 to about 20cartridges (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 12 or 15 cartridges) thatcontain fuel and a single cartridge that contains electrolyte. Oncethere is only one fuel cartridge left, the user will know that it istime to replace the electrolyte as well.

[0069] In one embodiment of the combination of fuel cell and cartridgeaccording to the present invention, the chambers of the fuel cell andthe chamber(s) of the cartridge each have at least one sealable opening.The sealable openings of the chambers of the fuel cell and the sealableopening(s) of the chamber(s) of the cartridge preferably are configuredto be capable of forming a liquid-tight passageway for liquid flowingbetween a chamber of the fuel cell and the corresponding chamber of thecartridge. Preferably, each chamber of the fuel cell and each chamber ofthe cartridge will have two sealable openings which are disposed at orclose to opposite ends of the respective chamber, and the sealableopenings of each chamber of the fuel cell and the sealable openings ofeach chamber of the cartridge are disposed with respect to each other toallow a substantially simultaneous flow of spent and replenishingliquids into and out of each chamber. A non-limiting example of such acombination of sealable openings and the operation thereof is describedbelow in the section “DETAILED DESCRIPTION OF THE PRESENT INVENTION”.

[0070] Moreover, the cartridge preferably comprises a pumping mechanismfor pushing the fluid in a chamber thereof into a corresponding chamberof the fuel cell. A non-limiting example of such a pumping mechanism isdescribed below in the section “DETAILED DESCRIPTION OF THE PRESENTINVENTION”.

[0071] The fuel cell of the present invention can be used to supplyelectrical energy to a virtually unlimited number of devices, inparticular, electric and electronic devices such as, e.g., (cellular)phones, (portable) computers, PDAs, consumer electronics, (portable)medical devices and components and peripherals thereof (such as, e.g.,wireless computer keyboards and mice). As a general rule, the fuel cellof the present invention can be employed for all devices for whichconventional batteries (such as, e.g., AA batteries) can be used.

BRIEF DESCRIPTION OF THE DRAWINGS

[0072] The present invention is further described in the detaileddescription which follows, in reference to the noted plurality ofdrawings by way of non-limiting examples of exemplary embodiments of thepresent invention, in which like reference numerals represent similarparts throughout the several views of the drawings, and wherein:

[0073]FIG. 1 is a perspective view of a refillable fuel cell system(combination), having a refillable fuel cell and a refilling device(cartridge), that is constructed and operable in accordance with thepresent invention;

[0074]FIG. 2 is an exploded perspective view of the refillable fuel cellof FIG. 1;

[0075]FIG. 3 is a cross-sectional view of the refillable fuel cell ofFIG. 1 through a plane which is parallel to lines A-A;

[0076]FIG. 4 is an exploded perspective view of a turbulence reducing 10arrangement of the refillable fuel cell of FIG. 2;

[0077]FIG. 5a is an exploded perspective view of the refilling device ofFIG. 1;

[0078]FIG. 5b is a cross-sectional view of the refilling device of FIG.1 through a plane which is parallel to lines B-B;

[0079]FIG. 6 is an axial sectional view of a valve arrangement, prior tocoupling, for use with the refillable fuel cell system of FIG. 1;

[0080]FIG. 7 is an axial sectional view of the valve arrangement of FIG.6 which is partially coupled;

[0081]FIG. 8 is an axial sectional view of the valve arrangement of FIG.6 which is fully coupled;

[0082]FIG. 9 is a perspective view of the refillable fuel cell system ofFIG. 1 which is interlocked;

[0083]FIG. 10 is a cross sectional view, through a plane which isparallel to lines A-A, of the refillable fuel cell system of FIG. 9prior to refilling the refillable fuel cell;

[0084]FIG. 11 is a cross sectional view, through a plane which isparallel to lines A-A, of the refillable fuel cell system of FIG. 9during refilling the refillable fuel cell; and

[0085]FIG. 12 is a cross sectional view, through a plane which isparallel to lines A-A, of the refillable fuel cell system of FIG. 9after refilling the refillable fuel cell.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0086] The particulars shown herein are by way of example and forpurposes of illustrative discussion of the embodiments of the presentinvention only and are presented in the cause of providing what isbelieved to be the most useful and readily understood description of theprinciples and conceptual aspects of the present invention. In thisregard, no attempt is made to show structural details of the presentinvention in more detail than is necessary for the fundamentalunderstanding of the present invention, the description taken with thedrawings making apparent to those skilled in the art how the severalforms of the present invention may be embodied in practice.

[0087] Reference is now made to FIG. 1, which is a perspective view of arefillable fuel cell system 10, having a refillable fuel cell 12 and arefilling device (cartridge) 14, that is constructed and operable inaccordance with an aspect of the present invention. As the refillablefuel cell 12 produces electricity, the liquid fuel and the electrolyteof refillable fuel cell 12 are gradually exhausted of their usefulcomponents and are defined as spent liquid fuel and spent electrolyte. Anon-limiting example of a suitable fuel is a suspension of NaBH₄ in anNaBH₄ saturated KOH solution, as described in co-pending U.S.application Ser. No. 10/230,204, supra. A non-limiting example of asuitable liquid electrolyte is KOH solution. The spent liquid fuel andthe spent electrolyte are removed from refillable fuel cell 12 and areplacement liquid fuel and a replacement electrolyte are introducedinto refillable fuel cell 12 by refilling device 14. In accordance witha preferred embodiment of the present invention, the spent liquids areremoved from refillable fuel cell 12 into refilling device 14 andreplacement liquids are inserted by refilling device 14 into refillablefuel cell 12 substantially simultaneously. Moreover, refilling device 14stores the spent liquids in substantially the same volume that thereplacement liquids were stored. However, it should be noted that fuelsand electrolyte are still maintained in separate volumes withinrefilling device 14. In accordance with another embodiment of thepresent invention, the removal of the spent liquids and the insertion ofthe replacement liquids are not performed simultaneously. In accordancewith yet another embodiment of the present invention, the refillingdevice 14 stores the spent liquids and the replacement liquids inseparate volumes.

[0088] Reference is now made to FIGS. 2 and 3. FIG. 2 is an explodedperspective view of refillable fuel cell 12. Refillable fuel cell 12 hasa fuel cell assembly 16. Fuel cell assembly 16 includes two electrodeassemblies 18, which share a common fuel chamber 30. The choice of thenumber of electrode assemblies and their dimensions are designconsiderations which depend on the required electrical output, as willbe apparent to one of ordinarily skilled in the art. Fuel cell assembly16 also includes a bottom housing (casing) portion 58, a top housing(casing) portion 60, three gas evacuation devices 62, two side casings64, a central housing (casing) portion 68 and a plurality of conductiveplates 66.

[0089] Reference is now made to FIG. 3, which is a cross-sectional viewof refillable fuel cell 12 of FIG. 1 through a plane which is parallelto lines A-A. In this embodiment, each electrode assembly 18 includes acathode 22 having two surfaces 20, 21. At least 80% of surface 20 isexposed to air. Each electrode assembly 18 also includes an anode 24having two surfaces 26, 27. Fuel cell assembly 16 preferably alsoincludes two electrolyte chambers 28. Each electrolyte chamber 28contains an electrolyte and preferably is defined at least partially bybottom housing portion 58, top housing portion 60, surface 21 of cathode22 and surface 26 of anode 24. Fuel chamber 30, which contains a liquidfuel, is disposed between electrolyte chambers 28. Fuel chamber 30 isdefined at least partially by bottom housing portion 58, top housingportion 60, surfaces 27 of anode 24, which faces out of electrodeassemblies 18. Fuel chamber 30 preferably has two openings, a loweropening 34 and an upper opening 36. Reference is again made to FIG. 2.Lower opening 34 preferably is provided with a normally-sealed fluidtransfer port, exemplified by a valve 38, and upper opening 36 isprovided with a normally-sealed fluid transfer port, exemplified by avalve 40. Valve 38 and valve 40 are normally sealed. Valve 38 isdisposed below the fluid level of the liquid fuel in fuel chamber 30.Valve 38 is disposed in the lower section of fuel chamber 30 and valve40 is disposed in the upper section of fuel chamber 30. This, togetherwith other precautions described below, helps to ensure that, when valve38 and valve 40 are open and a replacement liquid fuel is introducedinto fuel chamber 30 via valve 38 and the existing liquid fuel isremoved from fuel chamber 30 via valve 40, the replacement liquid fueland the existing liquid fuel flow in a substantially laminar mannerwithin fuel chamber 30 which helps reduce mixing of the existing and thereplacement liquid fuel. This concept can also be understood by definingthe majority of the flow of the existing and replacement liquid fuelflowing through chamber 30 by a plurality of substantially parallelprimary flow vectors. The distance between valve 38 and valve 40measured parallel to the primary flow vectors is generally equal to themaximum dimension of chamber 30 measured parallel to the primary flowvectors. Fuel cell assembly 16 also includes a turbulence reducingarrangement 50 which further enhances laminar flow, as described above,within fuel chamber 30. Turbulence reducing arrangement 50 will bedescribed below in more detail with reference to FIG. 4. Electrolytechamber 28 is generally similar to fuel chamber 30. For example, eachelectrolyte chamber 28 has two openings, a lower opening 42 and an upperopening 44 (FIG. 3). Lower opening 42 is provided with a valve 46 andupper opening 44 is provided with a valve 48. Valve 46 and valve 48 areperform similar functions to valve 38 and valve 40 of fuel chamber 30,respectively.

[0090] Reference is now made to FIG. 4, which is an exploded perspectiveview of turbulence reducing arrangement 50. Turbulence reducingarrangement 50 is disposed within fuel chamber 30. In the case shownhere where filling is from the bottom of the chambers, turbulencereducing arrangement 50 is preferably close to the bottom of thechamber, i.e., near the inlet (see FIGS. 2, 3). Turbulence reducingarrangement 50 may be implemented in many ways including, but notlimited to, a layer of permeable material 52, such as permeable foam,which provides hydraulic damping. By way of a non-limiting example, thepermeable foam can be non-woven polypropylene foam with a weight ofbetween 80 and 100 grams per square meter. In the example shown here,layer of permeable material 52 is disposed between two mesh layers 54which serve to retain layer of permeable material 52. Layer of permeablematerial 52 and mesh layers 54 are held in place by a frame 56.Turbulence reducing arrangement 50 is disposed horizontally within fuelchamber 30, i.e., generally substantially perpendicular to the primarydirection of fluid flow during refilling. When valve 38 (FIG. 2) andvalve 40 (FIG. 2) are open and a replacement liquid is introduced intofuel chamber 30, layer of permeable material 52 helps disperse thereplacement liquid fuel which is entering fuel chamber 30 across fuelchamber 30 to promote laminar flow of the replacement liquid fuel. Itshould be noted that all orientations, for example: bottom, horizontaletc., are used for the sake of brevity assuming the device is standingupright as shown, but, the invention can alternatively be implemented inother orientations.

[0091] Referring briefly to FIG. 2, it will be appreciated that gasesaccumulate in chamber 30 and chambers 28. These accumulated gases needto be evacuated from refillable fuel cell 12 without allowing any of theliquids to escape. Therefore, one gas evacuation device 62 is disposedabove each of chamber 30 and chambers 28. Each gas evacuation device 62is configured to enable escape of accumulated gas and to prevent escapeof liquids. Gas evacuation device 62 may be implemented as any suitableopening or valve which equalizes gas pressure while preferably providingprotection against spillage of the liquids within the chambers.

[0092] Reference is now made to FIG. 5a, which is an explodedperspective view of refilling device 14. FIG. 5b is a cross-sectionalview of the refilling device of FIG. 1 through a plane which is parallelto lines B-B. Refilling device 14 has the form of a fluid replacementassembly 70. Fluid replacement assembly 70 has a main body 94, a tophousing portion 96, a bottom housing portion 98, a front cover 100 and aplurality of sealing gaskets 102. Fluid replacement assembly 70 includesa parallel-walled chamber 72 containing a replacement liquid fuel.Chamber 72 is mainly defined by main body 94, top housing portion 96 andbottom housing portion 98. Chamber 72 has an upper valve 74 and a lowervalve 76. Upper valve 74 is configured for coupling with valve 40 (FIG.2) and lower valve 76 is configured for coupling with valve 38 (FIG. 2).Chamber 72 also includes a fluid flow actuating arrangement 78 which isconfigured to substantially simultaneously remove the spent liquid fuelfrom refillable fuel cell 12 via valve 74 and supply the replacementliquid fuel to refillable fuel cell 12 via valve 76. Fluid flowactuating arrangement 78 includes a piston 88 which is configured tomove vertically within chamber 72 (i.e., to slide up and down within thechamber 72 in a sealed manner). Upper valve 74 is disposed near the topof chamber 72 and lower valve 76 is disposed near the bottom of chamber72 such that, when lower valve 76 and upper valve 74 are open, the spentliquid fuel entering chamber 72 via upper valve 74 is kept substantiallyseparate from the replacement fluid exiting chamber 72 via lower valve76 by piston 88. Piston 88 is spring loaded by a main piston spring MPSwhich in this case is a circular wire spring. Piston 88 also includes amain retaining rod 89 which is generally interlocked with a shaped slotin a release bar 92. Retaining rod 89 and release bar 92 arecollectively defined as a retaining arrangement. Retaining rod 89 isreleased by lateral displacement of release bar 92 causing a release ofpiston 88. A safety lock 90 prevents releasing of piston 88 byaccidentally displacing release bar 92. Fluid replacement assembly 70also includes two parallel walled chambers 80 containing a replacementelectrolyte. Two chambers 80 are mainly defined by main body 94, tophousing portion 96 and bottom housing portion 98. Each chamber 80 has anupper valve 82 and a lower valve 84. Upper valves 82 are configured forcoupling with valves 48 (FIG. 2) and lower valves 84 are configured forcoupling with valves 46 (FIG. 2). Each chamber 80 also includes a fluidflow actuating arrangement (pumping mechanism) 86 which is configured tosubstantially simultaneously remove spent electrolyte from refillablefuel cell 12 via valve 82 and supply replacement electrolyte torefillable fuel cell 12 via valve 84. Fluid flow actuating arrangement86 and upper valve 82 and lower valve 84 can also be configuredsubstantially the same as the corresponding elements of chamber 72. Eachpiston 86 is also spring loaded by a piston spring PS which in this caseis a circular wire spring. Piston 86 also includes a retaining rod RRwhich is generally interlocked with a shaped slot in a release bar 92.It will be apparent to those skilled in the art that refilling device 14can be used to replace other liquids. Additionally, refilling device 14can be implemented with one or more chambers.

[0093] In particularly preferred implementations, refilling device 14 isimplemented as a disposable device produced primarily from lightweightlow-cost materials. For this reason, at least the main body of thedevice (main body 94, top housing portion 96 and bottom housing portion98) are preferably made of polymer materials which are suitable towithstand exposure to the chemicals used. In practice, substantially allcomponents of the refilling device 14 (other than those with specificmechanical requirements such as springs) are preferably made from suchpolymer materials.

[0094] Reference is now made to FIGS. 6, 7 and 8. It will be understoodthat the liquid transfer ports and docking ports of the fuel cell andrefilling device, respectively, are configured to mate in order to allowreplacement of the fuel cell liquids, and must reseal on separation toprevent leakage of the contained liquids from either device. To thisend, the preferred features of these ports include reliable non-dripmating and resealing, while maximizing flow rates as much as possiblewhen open. It will be understood that any ports which provide thesefeatures may be used. Preferred examples include, but are not limitedto, mechanically interlocking valves and self-sealing plugs pierced byhollow needles. One particularly preferred implementation will now beexemplified with reference to FIGS. 6-8.

[0095]FIG. 6 is an axial sectional view of a valve arrangement 104,prior to coupling, for use with refillable fuel cell system 10 ofFIG. 1. FIG. 7 is an axial sectional view of valve arrangement 104 ofFIG. 6 which is partially coupled. FIG. 8 is an axial sectional view ofvalve arrangement 104 of FIG. 6 which is fully coupled. By way ofintroduction, the valves, alternatively described as ports, of thepresent invention and their coupling, alternatively described asdocking, are subject to design constraints which include the followingfactors. First, the dead space between the valves needs to be minimizedto prevent liquids dripping from the exterior of the valves after theliquids have been replaced. Second, other precautions need to beincorporated to prevent dripping. Third, the cross-sectional area of thevalves needs to be as large as possible to ensure good flow rates. Byway of example, valve arrangement 104 illustrates the coupling of uppervalve 74 and valve 40. However, it should be noted that correspondingvalves (i.e., valves 76 & 38, 82 & 48, and 84 & 46) of refillable fuelcell 12 and refilling device 14 are configured to operate insubstantially the same way as upper valve 74 and valve 40. Valve 40includes a plunger 112 having an alignment portion 106. Alignmentportion 106 is typically a hollow tube. Valve 40 also includes outertube 108 having a bore which tapers toward an end 110. Plunger 112 andalignment portion 106 are disposed within outer tube 108, plunger 112being disposed toward end 110. Alignment portion 106 has one or moreholes 114 through the side of alignment portion 106. Alignment portion106 also tapers toward end 110 to enable liquid to pass through holes114 when valve 40 is open. It should be noted, that when alignmentportion 106 is implemented as a hollow tube, holes 114 are needed.However, if alignment portion 106 is implemented in a different way,such as a X-cross-section tail, holes 114 may not be necessary. AnO-ring 116 is disposed between plunger 112 and outer tube 108 to ensurea strong seal of valve 40 when valve 40 is closed. O-ring 116 isdisposed, as close to end 110 as possible, to minimize any dead spacebetween valve 40 and upper valve 74. Valve 40 also includes a spring 118and a stop ring 120. Stop ring 120 is mechanically connected to outertube 108, and spring 118 is disposed between stop ring 120 and theinside of alignment portion 106, such that spring 118 pushes and/orbiases alignment portion 106 and plunger 112 toward end 110 to sealvalve 40. Valve 40 also has a front outer O-ring 122 disposed on theouter surface of outer tube 108 toward end 110 and a rear outer O-ring123 arranged at another end of the valve 40.

[0096] Upper valve 74 is constructed in a substantially similar way(i.e., internally) as valve 40. Additionally, upper valve 74 includes areceiving port 124 and an opening pin 126. Receiving port 124 isconfigured to receive outer tube 108 of valve 40 such that, valve 40 andupper valve 74 are sealably coupled by O-ring 122 being in close contactwith receiving port 124, prior to either of valve 40 or upper valve 74opening (FIG. 7). Opening pin 126 is connected to plunger 112 of uppervalve 74 such that, when valve 40 and upper valve 74 are pushedtogether, opening pin 126 causes valves 40, 74 to open (FIG. 8). Oncevalves 40, 74 are open, liquid can flow through valves 40, 74 via holes114 in alignment portion 106.

[0097] Reference is now made to FIG. 8. Receiving port 124 preferablyincludes an absorbent member 128 which is disposed between valve 40 andupper valve 74. Absorbent member 128 is deployed to absorb any remainingliquid which is disposed between valve 40 and upper valve 74 aftervalves 40, 74 are sealed by being pulled apart. Absorbent member 128 hasan absorbency capacity with respect to the liquid flowing through valvearrangement 104. For the purpose of the description and claims, the“absorbency capacity” is here defined as the volume of liquid that canbe absorbed by member 128 without dripping. To the extent that theabsorbency capacity thus defined varies as a function of the liquidcomposition, water may arbitrarily be chosen as a reference fluid forthe purpose of defining this property. Clearly, however, it is theabsorbency with respect to the actual liquid fuel which defines thedesired characteristics of the system, as described below. Preferredtypes of material for absorbent member 128 are chosen to have propertiessuch that they expand beyond their initial volume as they absorb liquid,thereby absorbing a volume of liquid greater than the initial externalvolume of the member. By way of a non-limiting example, absorbent member128 can be a SIF felt grade hydrophobic foam, which is commerciallyavailable from Foamex International (Eddystone, Pa.). When valves 40, 74are sealed by being pulled apart, they define a dead space 130therebetween. In particularly preferred implementations of the presentinvention, the absorbency capacity of absorbent member 128 is greaterthan or equal to the total dead space volume between the valves at themoment of sealing. This arrangement has been found highly effective inpreventing spilling of any liquid residue trapped between valve 40 andvalve 74 after valves 40, 74 are sealed. It will be apparent to thoseskilled in the art that valve arrangement 104 can be used with manyapplications, especially those applications requiring non-drip valvearrangements with similar design requirements.

[0098] Reference is now made to FIG. 9, which is a perspective view ofrefillable fuel cell system 10 of FIG. 1 in an interlocked and connectedposition. Reference is also now again made to FIG. 1. Refillable fuelcell system 10 has an interlocking mechanism 132. Interlocking mechanism132 has a component 134 which is mechanically attached to fuel cellassembly 16 of refillable fuel cell 12 and a component 136 which ismechanically attached to fluid replacement assembly 70 of refillingdevice 14. To begin removing the spent liquids of refillable fuel cell12 and to refill refillable fuel cell 12 with replacement liquids,valves 38, 40, 46 and 48 of refillable fuel cell 12 are lined up and/oraligned with corresponding valves 74, 76, 82, 84 of refilling device 14.Refillable fuel cell 12 and refilling device 14 are then pushed togetherand interlocking mechanism 132 is engaged to maintain the pushingtogether of valves 38, 40, 46, 48, 74, 76, 82, 84. Valves 38, 40, 46,48, 74, 76, 82, 84 are now open.

[0099] Reference is now made to FIG. 10, which is a cross sectionalview, through a plane which is parallel to lines A-A, of fuel chamber 30and chamber 72 of refillable fuel cell system 10 of FIG. 9 prior torefilling refillable fuel cell 12. Once, valves 38, 40, 74, 76, areopen, fuel chamber 30 and chamber 72 define a closed fluid systemcontaining the spent liquid fuel and the replacement liquid fuel,respectively. At this point, piston 88 is at the top of chamber 72.Piston 88 substantially prevents the liquids flowing through valves 38,40, 74, 76.

[0100] Reference is now made to FIG. 11, which is a cross sectionalview, through a plane which is parallel to lines A-A, of fuel chamber 30and chamber 72 of refillable fuel cell system 10 of FIG. 9 duringrefilling refillable fuel cell 12. Safety lock 90 (FIGS. 5a, 5 b) isremoved from release bar 92 (FIGS. 5a, 5 b) and then release bar 92 isdisplaced laterally to release retaining rod 89, thereby releasingspring loaded piston 88. Piston 88 is pushed down through chamber 72 bythe spring of piston 88. In this way, piston 88 pushes the replacementliquid fuel out of chamber 72 via lower valve 76 and into fuel chamber30 via valve 38. The replacement liquid fuel enters fuel chamber 30 viaturbulence reducing arrangement 50 which substantially prevents mixingof the spent and the replacement liquid fuels in fuel chamber 30.Substantially simultaneously, piston 88 draws in the spent liquid fuelfrom fuel chamber 30 via valve 40 of fuel chamber 30 and upper valve 74of chamber 72. Additionally, the replacement liquid fuel entering fuelchamber 30 pushes the spent liquid fuel upward towards valve 40. Mixingof the spent and replacement liquids is substantially prevented inchamber 72 by piston 88, as described above with reference to FIGS. 5a,5 b. It should also be noted that the spent liquid fuel generally has alower density than the replacement liquid fuel and therefore it may beadvantageous for the replacement liquid fuel to enter fuel chamber 30from the bottom thereof. However, it will be clear to one of ordinarilyskill in the art that the invention can be modified such that, thereplacement liquid fuel enters fuel chamber 30 from the top thereof andthe spent liquid fuel exits chamber 30 from the bottom thereof.

[0101]FIG. 12 is a cross sectional view, through a plane which isparallel to lines A-A, of fuel chamber 30 and chamber 72 of refillablefuel cell system 10 of FIG. 9 after refilling refillable fuel cell 12.Refillable fuel cell 12 now contains the replacement liquid fuel andrefilling device 14 now contains the spent liquid fuel. Similarly, thespent electrolyte has been removed from refillable fuel cell 12 torefilling device 14 and substantially simultaneously, the replacementelectrolyte has been inserted into refillable fuel cell 12 fromrefilling device 14. The replacement of the spent liquid fuel and thespent electrolyte is performed substantially simultaneously.

[0102] It is noted that the foregoing examples have been provided merelyfor the purpose of explanation and are in no way to be construed aslimiting of the present invention. While the present invention has beendescribed with reference to exemplary embodiments, it is understood thatthe words which have been used herein are words of description andillustration, rather than words of limitation. Changes may be made,within the purview of the appended claims, as presently stated and asamended, without departing from the scope and spirit of the presentinvention in its aspects. Although the present invention has beendescribed herein with reference to particular means, materials andembodiments, the present invention is not intended to be limited to theparticulars disclosed herein; rather, the present invention extends toall functionally equivalent structures, methods and uses, such as arewithin the scope of the appended claims.

What is claimed is:
 1. A fuel cell comprising: a casing; a cathodehaving a first surface and a second surface; at least part of the secondsurface being exposed to the atmosphere; an anode having a first surfaceand a second surface; a first chamber configured to retain liquid fuel,wherein the first chamber is defined at least partially by the firstsurface of the anode; and a second chamber configured to retain liquidelectrolyte, wherein the second chamber is defined at least partially bythe second surface of the anode and the first surface of the cathode,wherein the fuel cell is configured to be sealed in a substantiallyliquid-tight manner during at least a portion of its service life. 2.The fuel cell of claim 1, wherein the fuel cell is configured to bedisconnected from a fuel delivery system during at least a portion ofthe service life.
 3. The fuel cell of claim 1, wherein the casing isconfigured to be substantially liquid-tight regardless of orientation.4. The fuel cell of claim 1, wherein the first chamber is filled atleast partially with a liquid fuel and the second chamber is filled atleast partially with a liquid electrolyte.
 5. The fuel cell of claim 4,wherein the liquid fuel comprises a lower alcohol.
 6. The fuel cell ofclaim 4, wherein the liquid fuel comprises at least one of LiAlH₄, KBH₄,NaBH₄, LiBH₄, (CH₃)₃NHBH₃, NaAlH₄, NaCNBH₃, CaH₂, LiH, NaH, KH, Na₂S₂O₃,Na₂HPO₃, Na₂HPO₂, K₂S₂O₃, K₂HPO₃, K₂HPO₂, NaCOOH and KCOOH.
 7. The fuelcell of claim 4, wherein the liquid electrolyte comprises an aqueousinorganic hydroxide.
 8. The fuel cell of claim 1, wherein the cathodecomprises an air-breathing cathode.
 9. The fuel cell of claim 1, whereinthe anode comprises a metal that is capable of catalyzing anelectrochemical oxidation of the liquid fuel.
 10. The fuel cell of claim1, wherein the fuel cell lacks a membrane.
 11. The fuel cell of claim 1,wherein the first chamber is configured to retain about 2000 ml ofliquid fuel.
 12. The fuel cell of claim 11, wherein the first chamber isconfigured to retain from between about 1 to about 1000 ml of liquidfuel.
 13. The fuel cell of claim 1, wherein the second chamber isconfigured to retain up to about 1000 ml of liquid electrolyte.
 14. Thefuel cell of claim 13, wherein the second chamber is configured toretain from between about 0.5 to about 500 ml of liquid electrolyte. 15.The fuel cell of claim 1, wherein the casing has a generally rectangularouter shape.
 16. The fuel cell of claim 15, wherein a largest outerdimension of the casing is less than or equal to about 50 cm.
 17. Thefuel cell of claim 1, wherein the fuel cell comprises a free innervolume of about 4000 ml.
 18. The fuel cell of claim 17, wherein the freeinner volume is between about 1.5 and about 3000 ml.
 19. The fuel cellof claim 1, wherein at least one of the cathode and the anode comprisesa surface area of between about 0.5 and about 500 cm².
 20. The fuel cellof claim 1, wherein at least a portion of the casing comprises a plasticmaterial.
 21. The fuel cell of claim 20, wherein the plastic materialcomprises at least one of polyolefin, polycarbonate, polyvinylchloride,acrylonitrile-butadiene-styrene terpolymer, polyurethane,polytetrafluoroethylene and silicone rubber.
 22. The fuel cell of claim1, wherein at least a portion of the casing comprises at least one of ametal and a metal alloy.
 23. The fuel cell of claim 22, wherein at leasta portion of the casing comprises at least one of stainless steel,nickel, chromium and titanium.
 24. The fuel cell of claim 1, wherein thecasing comprises at least one sealable opening communicating with eachof the first and second chambers.
 25. The fuel cell of claim 1, whereinthe casing comprises ports which are configured for multiple opening andresealing operations.
 26. The fuel cell of claim 1, wherein the casingcomprises two sealable openings in fluid communication with each of thefirst and second chambers.
 27. The fuel cell of claim 26, wherein eachthe two sealable openings comprises oppositely arranged openings. 28.The fuel cell of claim 1, wherein the casing comprises valves.
 29. Thefuel cell of claim 1, wherein the second surface of the anode and thefirst surface of the cathode are substantially parallel to each other.30. The fuel cell of claim 1, wherein the fuel cell comprises one firstchamber and one second chamber.
 31. The fuel cell of claim 1, whereinthe fuel cell comprises one first chamber and two second chambers. 32.The fuel cell of claim 1, wherein the fuel cell comprises two firstchambers and two second chambers.
 33. The fuel cell of claim 1, whereinthe fuel cell comprises at least another cathode, at least anotheranode, and another second chamber for retaining liquid electrolyte. 34.The fuel cell of claim 33, wherein the fuel cell comprises anotheranode, another cathode, a single first chamber and another secondchamber.
 35. The fuel cell of claim 34, wherein the second chamber isdefined by the anode and the cathode and wherein the other secondchamber is defined by the other anode and the other cathode.
 36. Thefuel cell of claim 1, wherein the casing comprises at least one sealableopening for allowing gas generated during an operation of the fuel cellto escape to the atmosphere.
 37. The fuel cell of claim 1, wherein thefuel cell further comprises an ancillary power supply device for peakpower requirements.
 38. The fuel cell of claim 37, wherein the ancillarypower supply device comprises a supercapacitor.
 39. A self-contained,refillable fuel cell comprising: a cathode having a first surface and asecond surface, at least part of the second surface being exposed to theatmosphere; an anode having a first surface and a second surface; afirst chamber filled at least partially with a liquid fuel, the firstchamber being defined at least partially by the first surface of theanode; a second chamber filled at least partially with a liquidelectrolyte, the second chamber being defined at least partially by thesecond surface of the anode and the first surface of the cathode; atleast one sealable opening communicating with the first chamber; and atleast one other sealable opening communicating with the second chamber,wherein the fuel cell is configured to at least one of receive freshliquid and discharge spent liquid via the sealable openings.
 40. Thefuel cell of claim 39, wherein the first and second chambers eachcommunicate with two sealable openings, one for discharging spent liquidand one receiving fresh liquid.
 41. A cartridge for refreshing the fuelcell of claim 39, wherein the cartridge comprises at least one of a fuelchamber at least partially filled with liquid fuel and an electrolytechamber at least partially filled with liquid electrolyte.
 42. Thecartridge of claim 41, wherein the cartridge comprises each of the fuelchamber and the electrolyte chamber and wherein the fuel and electrolytechambers are each in fluid communication with at least one sealableopening.
 43. The cartridge of claim 42, wherein the fuel and electrolytechambers are each in fluid communication with two oppositely arrangedsealable openings.
 44. The cartridge of claim 43, wherein each sealableopening comprises a valve.
 45. The cartridge of claim 41, wherein theliquid fuel comprises a lower alcohol.
 46. The cartridge of claim 45,wherein the lower alcohol comprises at least one of methanol andglycerol.
 47. The cartridge of claim 45, wherein the liquid fuelcomprises at least one of LiAlH₄, KBH₄, NaBH₄, LiBH₄, (CH₃)₃NHBH₃,NaAlH₄, NaCNBH₃, CaH₂, LiH, NaH, KH, Na₂S₂O₃, Na₂HPO₃, Na₂HPO₂, K₂S₂O₃,K₂HPO₃, K₂HPO₂, NaCOOH and KCOOH.
 48. The cartridge of claim 41, whereinthe liquid electrolyte comprises an aqueous hydroxide.
 49. The cartridgeof claim 48, wherein the aqueous hydroxide comprises potassiumhydroxide.
 50. The cartridge of claim 41, wherein the fuel chamber isconfigured to retain up to about 2500 ml of liquid fuel.
 51. Thecartridge of claim 50, wherein the fuel chamber is configured to retainfrom about 1.5 to about 1250 ml of liquid fuel.
 52. The cartridge ofclaim 41, wherein the electrolyte chamber is configured to retain up toabout 1500 ml of liquid electrolyte.
 53. The cartridge of claim 52,wherein the electrolyte chamber is configured to retain from about 1 toabout 750 ml of liquid electrolyte.
 54. The cartridge of claim 41,wherein the cartridge comprises a generally rectangular outer shape. 55.The cartridge of claim 54, wherein a largest outer dimension of thecartridge is not larger than about 50 cm.
 56. The cartridge of claim 41,wherein the cartridge comprises a free inner volume which is equal to orless than about 5000 ml.
 57. The cartridge of claim 56, wherein the freeinner volume is between about 2 to about 4000 ml.
 58. The cartridge ofclaim 41, wherein at least a portion of the cartridge comprise a plasticmaterial.
 59. The cartridge of claim 58, wherein the plastic materialcomprises at least one of polyolefin, polycarbonate, polyvinylchloride,acrylonitrile-butadiene-styrene terpolymer, polyurethane,polytetrafluoroethylene and silicone rubber.
 60. The cartridge of claim41, wherein the cartridge comprises one fuel chamber and one electrolytechamber.
 61. The cartridge of claim 41, wherein the cartridge comprisesone fuel chamber and two electrolyte chambers.
 62. The cartridge ofclaim 41, wherein the cartridge comprises two fuel chambers and twoelectrolyte chambers.
 63. A packaged combination of a plurality ofcartridges for refreshing the fuel cell of claim 39, wherein thecombination comprises at least one first cartridge filled at leastpartially with liquid fuel and at least one second cartridge filled atleast partially with liquid electrolyte.
 64. The packaged combination ofclaim 63, wherein the combination comprises between about 1 and about 20first cartridges and one second cartridge.
 65. The combination of thefuel cell of claim 39 and a cartridge for refreshing at least one of theliquid fuel and the liquid electrolyte of the fuel cell.
 66. Thecombination of claim 65, wherein the cartridge comprises at least one ofa fuel chamber and an electrolyte chamber.
 67. The combination of claim66, wherein at least one of the fuel and electrolyte chambers of thefuel cell and at least one of the fuel and electrolyte chambers of thecartridge are in fluid communication with at least one sealable opening.68. The combination of claim 67, wherein the at least one sealableopening of one of the fuel and electrolyte chambers of the fuel cell andthe at least one sealable opening of one of the fuel and electrolytechambers of the cartridge are capable of capable of forming aliquid-tight passageway between the fuel cell and the cartridge.
 69. Thecombination of claim 67, wherein each of the fuel and electrolytechambers of the fuel cell and each of the fuel and electrolyte chambersof the cartridge are in fluid communication with two sealable openings.70. The combination of claim 68, wherein the cartridge is configured toreceive spent liquid fuel and spent liquid electrolyte from the fuelcell via the at least one sealable openings and is configured tointroduce fresh liquid fuel and fresh liquid electrolyte into the fuelcell via the at least one sealable openings.
 71. The combination ofclaim 66, wherein a volume ratio of one of the fuel and electrolytechambers of the fuel cell relative to one of the fuel and electrolytechambers of the cartridge is between about 1:1 and about 1:1.4.
 72. Thecombination of claim 66, wherein a volume ratio of liquid contained inthe fuel cell relative to liquid contained in the cartridge is betweenabout 1:1 and about 1:1.4.
 73. The combination of claim 66, wherein thecartridge comprises a pumping mechanism for causing liquid in thecartridge to enter the fuel cell.
 74. A method of supplying electricalenergy to a device, comprising providing a fuel cell comprising acathode having a first surface and a second surface, at least part ofthe second surface being exposed to the atmosphere, an anode having afirst surface and a second surface, a first chamber containing a liquidfuel, the first chamber being defined at least partially by the firstsurface of the anode, and a second chamber containing a liquidelectrolyte, the second chamber being defined at least partially by thesecond surface of the anode and the first surface of the cathode; andelectrically connecting the fuel cell to the device, wherein the fuelcell is sealed in a substantially liquid-tight manner and is notconnected to an external fuel delivery system while the fuel cellsupplies electrical energy to the device.
 75. The method of claim 74,wherein the liquid fuel comprises a lower alcohol.
 76. The method ofclaim 75, wherein the liquid fuel comprises at least one of LiAlH₄,NaBH₄, KBH₄, LiBH₄, (CH₃)₃NHBH₃, NaAlH₄, NaCNBH₃, CaH₂, LiH, NaH, KH,Na₂S₂O₃, Na₂HPO₃, Na₂HPO₂, K₂S₂O₃, K₂HPO₃, K₂HPO₂NaCOOH and KCOOH. 77.The method of claim 74, wherein the liquid electrolyte comprises anaqueous inorganic hydroxide.
 78. The method of claim 74, wherein thecathode comprises an air-breathing cathode.
 79. The method of claim 74,wherein the device is a portable device.
 80. The method of claim 74,wherein the device is an electronic device.
 81. The device of claim 74,wherein the device is a telecommunications device.
 82. The method ofclaim 74, wherein the device is at least one of a cellular phone,portable computer, PDA, audio device, video device, medical device and acomponent thereof.
 83. The combination of a device and a fuel cellconnected to the device wherein the fuel cell comprises a cathode havinga first surface and a second surface, at least part of the secondsurface being exposed to the atmosphere, an anode having a first surfaceand a second surface, a first chamber containing a liquid fuel, thefirst chamber being defined at least partially by the first surface ofthe anode, and a second chamber containing a liquid electrolyte, thesecond chamber being defined at least partially by the second surface ofthe anode and the first surface of the cathode, wherein the fuel cell issealed in a substantially liquid-tight manner and is not connected to anexternal fuel delivery system.
 84. The combination of claim 83, whereinthe liquid fuel comprises a lower alcohol.
 85. The combination of claim83, wherein the liquid fuel comprises at least one of LiAlH₄, KBH₄,NaBH₄, LiBH₄, (CH₃)₃NHBH₃, NaAlH₄, NaCNBH₃, CaH₂, LiH, NaH, KH, Na₂S₂O₃,Na₂HPO₃, Na₂HPO₂, K₂S₂O₃, K₂HPO₃, K₂HPO₂, NaCOOH and KCOOH.
 86. Thecombination of claim 83, wherein the liquid electrolyte comprises anaqueous hydroxide.
 87. The combination of claim 83, wherein the cathodecomprises an air-breathing cathode.
 88. The combination of claim 83,wherein the device is a portable telecommunications device.
 89. Thecombination of claim 83, wherein the device has a power capacity of upto about 150 W.
 90. The combination of claim 83, wherein the device isat least one of a cellular phone, portable computer, PDA, audio device,video device, medical device and a component thereof.
 91. A method ofrefreshing a self-contained fuel cell wherein the fuel cell comprises acathode having a first surface and a second surface, at least part ofthe second surface being exposed to the atmosphere, an anode having afirst surface and a second surface, a first chamber containing a liquidfuel, the first chamber being defined at least partially by the firstsurface of the anode, a second chamber containing a liquid electrolyte,the second chamber being defined at least partially by the secondsurface of the anode and the first surface of the cathode, wherein themethod comprises: connecting a cartridge to the fuel cell, wherein thecartridge comprises a fuel chamber that is filled at least partiallywith the liquid fuel and an electrolyte chamber that is filled at leastpartially with the liquid electrolyte.
 92. The method of claim 91,wherein the process further comprises coupling sealable openings of thecartridge with corresponding sealable openings of the fuel cell toestablish substantially liquid-tight passageways between the cartridgeand fuel cell and allowing liquid contained in the cartridge to flowinto the fuel cell and vice versa.
 93. A fuel cell system comprising: afuel cell assembly comprising a cathode having a first surface and asecond surface, at least part of said second surface being exposed toair, an anode having a first surface and a second surface, a firstchamber configured for containing a liquid fuel, said first chamberbeing defined at least partially by said first surface of said anode,wherein said first chamber has a first liquid transfer port and a secondliquid transfer port, said first and second ports being normally closed,a second chamber configured for containing a liquid electrolyte, saidsecond chamber being defined at least partially by said second surfaceof said anode and said first surface of said cathode, wherein saidsecond chamber has a third liquid transfer port and a fourth liquidtransfer port, said third and said fourth ports being normally closed;and a cartridge removably connected to the fuel cell.
 94. The system ofclaim 93, wherein each of said first, second, third and fourth ports areconfigured to open when the cartridge is connected to the fuel cell andare configured to close when the cartridge is disconnected from the fuelcell.
 95. The system of claim 93, wherein fuel cell is configured toreceive liquid fuel and electrolyte from the cartridge at a bottomportion of the fuel cell and is configured to discharge liquid fuel andelectrolyte from a top portion of the fuel cell.
 96. The system of claim93, further comprising a turbulence reducing arrangement disposed withinsaid first chamber, whereby the turbulence reducing arrangement isconfigured to reduce flow turbulence within said first chamber.
 97. Thesystem of claim 96, wherein said turbulence reducing arrangementincludes a layer of permeable material.
 98. The system of claim 93,wherein the cartridge comprises a first docking port and a seconddocking port, wherein the fuel cell comprises a third docking port and afourth docketing port, and wherein said first and second docking portsare configured to be respectfully connected to said third and saidfourth docketing ports.
 99. The system of claim 93, further comprisingat least one absorbent member arranged within a fluid communicationpassage between the fuel cell and the cartridge.
 100. The system ofclaim 99, wherein the at least one absorbent member is disposed withinat least one of said, first, second, third and fourth docking ports,whereby the at least one absorbent member has an absorbency capacity.101. The system of claim 93, further comprising a locking mechanism forlocking together the cartridge and the fuel cell.
 102. A fluidreplacement system for replacing a spent liquid contained in a fuel cellhaving a plurality of refilling ports, the fluid replacement systemcomprising; a storage chamber configured to contain a first replacementliquid; a first port in fluid communication with said storage chamber,said first port being connectable with one of the plurality of refillingports; a second port in fluid communication with said storage chamber,said second port being connectable with another of the plurality ofrefilling ports; and a fluid flow actuating arrangement configured toremove at least part of spent liquid from the fuel cell via said secondport and to supply at least some replacement liquid to the fuel cell viasaid first port.
 103. The system of claim 102, wherein said replacementliquid is a liquid fuel for a fuel cell.
 104. The system of claim 102,wherein said storage chamber is formed primarily from polymer materials.105. The system of claim 102, wherein said storage chamber has parallelwalls and said fluid flow actuating arrangement includes at least onepiston configured to move within said storage chamber.
 106. The systemof claim 102, wherein said fluid flow actuating arrangement comprises atleast one piston and at least one spring, wherein the at least onepiston acts to substantially separate spent liquid from the fuel celland replacement liquid.
 107. The system of claim 106, wherein the atleast one piston is biased by the at least one spring and said fluidflow actuating arrangement further comprises a retaining arrangementconfigured to retain and actuatably release said at least one piston.108. The system of claim 102, wherein said fluid flow actuatingarrangement comprises a safety lock configured to prevent an accidentalactuation.
 109. The system of claim 102, further comprising a firstabsorbent member disposed in an area of said first port and a secondabsorbent member disposed in an area of said second port.
 110. Thesystem of claim 102, further comprising an interlocking mechanism formaintaining fluid tight connections between the fuel cell and the fluidreplacement system.
 111. The system of claim 102, wherein said fluidreplacement assembly comprises a second storage chamber configured tocontain a second replacement liquid, a third port which is operationallyconnected to said second storage chamber, a fourth port, and a secondfluid flow actuating arrangement.
 112. The system of claim 111, whereinsaid second replacement liquid is an electrolyte for a fuel cell.
 113. Aport arrangement for transferring a liquid between a fuel cell and acartridge, the arrangement comprising: a first port; a second port; saidfirst port and said second port being configured to open when said firstport and said second port are connected together; an absorbent memberdisposed between said first port and said second port; said absorbentmember has an absorbency capacity; said first port and said second porttogether defining a dead space and being configured to close whendisconnected from each other; said dead space having a volume which isless than or equal to an absorbency capacity of said absorbent material.114. A liquid replacement method comprising: at least partially removingan at least partially spent liquid fuel from a first chamber of a fuelcell; and transferring a replacement liquid fuel into said firstchamber, wherein said removing and said transferring occur substantiallysimultaneously.
 115. The method of claim 114, wherein said removing andsaid transferring occur without mixing of said at least partially spentliquid fuel and said replacement liquid fuel.
 116. The method of claim114, wherein said removing and said transferring utilize substantiallylaminar fluid flow within said first chamber.
 117. The method of claim114, further comprising: at least partially removing an at leastpartially spent electrolyte from a second chamber of said fuel cell; andtransferring a replacement electrolyte into said second chamber, whereinsaid removing and said transferring occur substantially simultaneously.